<s>
The	O
MCP-1600	B-General_Concept
is	O
a	O
multi-chip	O
16-bit	B-Device
microprocessor	B-Architecture
introduced	O
by	O
Western	O
Digital	O
in	O
1975	O
and	O
produced	O
through	O
the	O
early	O
1980s	O
.	O
</s>
<s>
Used	O
in	O
the	O
Pascal	B-Device
MicroEngine	I-Device
,	O
the	O
WD16	B-General_Concept
processor	O
in	O
the	O
Alpha	O
Microsystems	O
AM-100	O
,	O
and	O
the	O
DEC	O
LSI-11	O
microcomputer	O
,	O
a	O
cost-reduced	O
and	O
compact	O
implementation	O
of	O
the	O
DEC	B-Device
PDP-11	I-Device
.	O
</s>
<s>
Internally	O
the	O
MCP-1600	B-General_Concept
is	O
a	O
(	O
relatively	O
fast	O
)	O
8-bit	O
processor	O
that	O
can	O
be	O
micro-programmed	O
to	O
emulate	O
a	O
16-bit	B-Device
CPU	O
.	O
</s>
<s>
Up	O
to	O
four	O
MICROMs	O
are	O
supported	O
,	O
but	O
usually	O
two	O
or	O
three	O
could	O
hold	O
the	O
needed	O
microprogram	B-Device
for	O
a	O
processor	O
.	O
</s>
<s>
Ten	O
may	O
be	O
addressed	O
directly	O
by	O
the	O
microinstruction	B-Device
(	O
Rx	O
)	O
,	O
four	O
may	O
be	O
addressed	O
either	O
directly	O
or	O
indirectly	O
(	O
Rx/Gx	O
)	O
,	O
and	O
the	O
remaining	O
12	O
may	O
be	O
addressed	O
only	O
indirectly	O
(	O
Gx	O
)	O
.	O
</s>
<s>
Indirect	O
addressing	O
is	O
via	O
a	O
3-bit	O
G	O
register	O
which	O
is	O
usually	O
loaded	O
with	O
the	O
register	O
field	O
of	O
the	O
PDP-11	B-Device
instruction	O
.	O
</s>
<s>
The	O
most	O
significant	O
feature	O
of	O
the	O
MCP-1600	B-General_Concept
is	O
its	O
Programmable	O
Translation	O
Array	O
(	O
PTA	O
)	O
.	O
</s>
<s>
The	O
PTA	O
serves	O
to	O
generate	O
new	O
microinstruction	B-Device
fetch	O
addresses	O
as	O
a	O
function	O
of	O
several	O
parameters	O
.	O
</s>
<s>
Essentially	O
a	O
macroinstruction	O
opcode	O
is	O
quickly	O
translated	O
into	O
an	O
address	O
that	O
is	O
loaded	O
onto	O
the	O
Location	O
Counter	O
,	O
creating	O
a	O
jump	O
to	O
the	O
appropriate	O
microcode	B-Device
to	O
handle	O
the	O
macroinstruction	O
.	O
</s>
<s>
Bill	O
Pohlman	O
was	O
the	O
design	O
engineering	O
manager	O
and	O
he	O
later	O
was	O
Project	O
Manager	O
for	O
the	O
Intel	B-General_Concept
8086	I-General_Concept
processor	O
.	O
</s>
<s>
In	O
March	O
1976	O
,	O
it	O
was	O
announced	O
that	O
National	O
Semiconductor	O
would	O
second-source	O
the	O
MCP-1600	B-General_Concept
.	O
</s>
<s>
The	O
Soviet	O
581	O
series	O
included	O
other	O
members	O
of	O
the	O
MCP-1600	B-General_Concept
family	O
as	O
well	O
.	O
</s>
<s>
cp16sim	O
is	O
an	O
open	O
source	O
MCP-1600	B-General_Concept
simulator	O
.	O
</s>
<s>
Written	O
in	O
C	B-Language
,	O
it	O
emulates	O
the	O
MCP-1600	B-General_Concept
processor	O
and	O
its	O
PTA	O
executing	O
the	O
code	O
found	O
on	O
the	O
WD9000	O
Pascal	B-Device
Microengine	I-Device
processor	O
.	O
</s>
<s>
"	O
It	O
works	O
well	O
enough	O
to	O
execute	O
the	O
first	O
few	O
dozen	O
p-code	O
instructions	O
of	O
the	O
ACD	O
PDQ-3	O
boot	O
ROM	B-Device
before	O
going	O
into	O
the	O
weeds.	O
"	O
</s>
<s>
It	O
is	O
released	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
version	O
3	O
.	O
</s>
